1. Field of the Invention
Methods and apparatuses consistent with the present invention relate to time synchronization, and more particularly, to synchronizing applications of network terminals.
2. Description of the Related Art
Various types of data are transmitted through a communication network. In particular, when data such as audio/video (AV) Streaming is transmitted/received, time synchronization between a transmitter and a receiver is very important, and the transmitter and receiver attempt synchronization using various algorithms while exchanging packets including time information.
FIG. 1 is a conceptual diagram for explaining a related art method of synchronizing applications of network terminals.
As shown in FIG. 1, in the related art, a dedicated application or a functional module within an application is used for time synchronization between two or more terminals connected to a network. There are various methods used for time synchronization. For example, the application of a terminal on a transmitter-side generates and transmits packets including time information to a terminal on a receiver-side, and the receiver-side terminal receives the packet. In this case, receiver-side terminal calculates accurate time of the transmitter-side terminal based on a processing delay and a network propagation delay of the transmitter-side terminal and a processing delay of the receiver-side terminal, and then synchronizes the time with the transmitter-side terminal. Alternatively, the applications of the transmitter-side terminal transmit the packets including the time information to the receiver-side terminals. Then the receiver-side terminal receives the packets and sends the response packet to the transmitter-side terminal. By a repetition of the frame exchange process, accurate timing of the transmitter-side terminal and the receiver-side terminal is calculated based on the processing delay, network propagation delay or the like in order to synchronize with a reference time, so that time synchronization is completed.
In the related art, there are various methods of time synchronization. In all the methods, synchronization is performed in the applications having a time synchronization function. However, a network interface provides a path for synchronization or “processing delay” information, but it does not directly perform any process of synchronization.
In other words, in many cases, in order to synchronize terminals connected to a network with other terminals, a Transmission Control Protocol/Internet Protocol (TCP/IP) protocol stack and a synchronization dedicated application or a functional module for time synchronization in an application are required.
However, low price consumer electronics (CE) products that include such a function require a high-end system, resulting in an increase in price. Moreover, the network terminals should exchange additional packets as well as data packets in order to perform time synchronization, and therefore network traffic increases.